add new 'internationalize' function to change number type
diff --git a/src/isup.hrl b/src/isup.hrl
index 7190deb..55750ea 100644
--- a/src/isup.hrl
+++ b/src/isup.hrl
@@ -91,6 +91,9 @@
-define(ISUP_PAR_USER_USER_IND, 2#00101010). % User-to-user indicators
-define(ISUP_PAR_USER_USER_INFO, 2#00100000). % User-to-user information
+-define(ISUP_ADDR_NAT_NATIONAL, 2#0000011). % National (significant) number
+-define(ISUP_ADDR_NAT_INTERNATIONAL, 2#0000100). % International number
+
-record(party_number, {
nature_of_addr_ind,
internal_net_num, % only in called party